These are caused as part of ASL's built in kernel vulnerability scanner. These messages in syslog are normal and harmless and you can ignore them. They mean the vulnerability scanner is working correctly. These messages do not cause any harm to the system, and are perfectly safe.

If you are running an ASL kernel you are immune to the vulnerabilities the scanner will test for and the "PAX:" messages indicate that ASL is working normally and safely.

If you are not running an ASL kernel you will not see the PAX: messages, which means you are vulnerable to some of these tests. The ASL GUI will report the specific vulnerabilities, you can also get a report from the command line by running this command as root:

asl -s

The solution to kernel level vulnerabilities is to run the ASL kernel. Standard Linux kernels are not immune to all kernel exploits and vulnerabilities.

Can I suppress these events so they are not logged?

No. These are generated by the kernel itself, and suppressing these events would mean that you wouldnt be notified of an actual attack on your system either. These messages mean that the kernel is working correctly, and this is an important part of the health management system in ASL.